Variable-control device



July 3, 1928. 1,675,377

l.. PAcEN-r VARIABLE CONTROL DE-VICE Filed April 6, 1925 2 Sheets-$heet 1 INVENTOR A TTORNE Y July 3, 1928. 1,675,377

L. G. PACI-:NT

VARIABLE CONTROL DEVICE Filed April 6. 192s 2 sheets-sheet 2 IZ Y* 1 *7 INVENTOR ATTORNEY l (is bil Patented July 3, 1928.

UITED qSTATES LOUIS G. PACENT, OF WINFIELD, NEW YORK.

VARIABLE-CONTROL DEVICE.

Application filed April 6,

This invention has to do with devices for manually controlling electrical apparatus, and, more especially, high frequency apparatus such as variable condensers, vel'iometers, and the like.

The invention relates, more particularly, to what are commonly termed Vernier adjustment devices, and specifically to control knobs and dials provided with instrumentalities for effecting very fine rotary adjustments of the electrical apparatus to which it may be attached.

.ln radio receiving instruments providedwith highly selective circuits, adjustments are frequently so critical that it is difficult to time in desired transmitting stations with the control knobs ordinarily provided. Under these circumstances it becomes desirable to equip the radio receiving' instrument with devices designed for e'ecting micrometric adjustments.

So called vernicr adjustment devices have heretofore been provided, particularlyfin conjunction with variable condensers. The most common of these is the well-known vernier condenser comprising two sets of rotatable plates mounted on concentric shafts and provided with concentric control knobs. One of the sets ol rotatable plates usually consists of a single plate which is operable to effect tine capacity adjustments, while the other set is operable for coarse adjustments. Other arrangements have been proposed which do not involve separately rotatable elements for the tine adjustments, but in so far as it has been possible to ascertain, none of these contemplates the provision of an integral shelf-contained device which is operable for making both coarse and fine adjustments.

The principal object of the presentinvent ion is to provide a simple device for effecting micromclric adjustments of ordinaryv variable electrical apparatus such as variable coi'idensers, verioineters, variof'ou-- plers and the like which can bc connected to the operating shafts of such apparatus and which does not necessitate any considerable alterations ot' the apparatus or panel on which it is mounted.

In accordance with the foregoing objects, the invention provides in its preferred embodiment a knob and dial which is adapted to be attached to the operating shaft of a variable electrical device in which is included a mechanism comprising speed reducfclearly in Fig. The member 1923. Serial N0. 630,221.

ing elements for making line adjustments, the entire structure being self-contained.

Certain features of the invention which have not been specifically mentioned above will be referred to in the detailed description hereinafter.

In the drawings,

Fig. 1 is a front elevational view of a control knob and dial in accordance with this invention;

Fig. 2 is a rear elevational view of the same device with a portion broken away in order to more clearly disclose the interior mechanism g Fig. 3 is a side elevational view of the vsame control knob and dial;

Fig. 4 is a cross-sectional view of the control knob shown in Figs. 1,2 and 3; and

Figs. 5 and (i are cross-sectional views of alternative forms of the invention.

Describing, first, the embodiment of the invention illustrated in Figs. l `to 4 inclusive, 1 represents a panel of insulating material, 2 is a rotatable shaft forming part of a variable electrical device such as a variable condenser or a variometer, 3 is a circular metal disc secured to the panel by `means of screws l and having an aperture at its center portion in which seated an annular member 5, the exterior of which is provided with gear teeth. as is shown most Y 5 is secured to the plate 3 in any convenient manner, and in the present instance by means of the screws 6. The bushing '7 is preferably of metal, and. is bored to receive shaft 2. A metal bushing 8 is bored to receive the bushing 7, and is threaded externally to engage the internal thread of the knob 9. This knob is referred to hereinafter as the main knob, The main knob, togcthcr with the bushings 7 and 8 and the shaft 2, are secured together and locked against relative rotation by the Set screw l0. which is threaded into the bushing 8. The main knob 9 and bushing 8 are concave, as shown, to receive the substantially spherical auxiliary knol) ll. A rotatable spindle l2 is secured in the auxiliary knob ll and journaled in an aperture provided therefor in the bushing Gear teeth 13 arc cut on the end ol' the spindle lf2, and these mesh with the gear teeth in member A set screw ll engages a groove on the spindle l2 and prevents withdrawal of the latter together with auxiliary knob 11.

It will be seen that the shaft 2 can be directly rotated by turning the main knob 9, which is rigidly connected thereto. By rotating the auxiliary knob 11 very fine adjustments may be effected because of the fact that the gear ratio between the gear member 5 and the pinion 13 is very large. This gear ratio preferably such that several revolutions of the auxiliary knob 11 are required to effect one revolution of the main knob 9.

While the axis of rotation of the auxiliary knob 11 is at an angie to that of the shaft 2, the external appearance of symmetry is maintained by reason of the fact that the main knob is of substantially spherical forni. It will be observed that no other form of auxiliary knob will give this symmetrical appearance with the mechanical design described.

The alternative structure illustrated in Fig. 5 is a modification of that shown in Figs. 1 to l inclusive. In this structure the members and 8 are eliminated, .The disc 15 is embossed at its center portion and provided with gear teeth for engaging pinion 13, thus eliminating the extra gear member 5 of the first described embodiment.

Fig. 6 is an alternative embodiment of the invention in which a friction drive is substituted for the gear drive of the previously described structures. Here the end of the spindle 1Q is formed conically to frictionally engage the conical surface of the disc 16, and a leaf spring 17 engages a. groove in the spindle 12 and functions to hold its conical end portion in frictional engagement with the conical hub of the disc 16.

It Will be noted that each of these alternative embodiments of the invention is entirely self-contained and that, accordingly, no assembling on the part of the user of these devices is required, it being merely necessary to slip the shaft of the apparatus to be operated into the bushing provided therefor and tighten up on the set screw 10. The stationary discs 13, 15, 1G are easily secured to the panel and require no alterations of the panel involving mechanical skill.

I claim:

1. The combination with a rotatable shaft of a main knob mounted thereon and rotatable with said shaft, a stationary member having gear teeth disposed concentrically with said shaft, an auxiliary knob partly disposed Within a recess in said main knob, a spindle rotatable by said auxiliary knob and having its axis of rotation disposed at an angle to said shaft, and a pinion rotatable by said spindle, said pinion being in mesh with said gear teeth, said knobs, said member, said spindle and said pinion being conibined in a self-contained unit.

2. A control device for variable electrical apparatus comprising a disc adapted to be lixedly secured to an apparatus panel, said disc having an apertured embossed portion, gear teeth integral With said embossed portion, a shouldered brushing inserted in the aperture in said embossed portion, the bore of said bushing being concentric with said gear teeth and adapted to receive a rotatable shaft, a main knob mounted on said bushing and rotatable therewith for rotating the said shaft, an auxiliary knob seated in a recess in said main knob, said auxiliary knob being adapted to rotate relatively to said main knob, a spindle secured to said auxiliary knob and rotatable therewith, said spindle being journaled in said main knob and having its axis of rotation disposed at an angle to the axis of rotation of said main knob, and a pinion integral .with the end portion of said spindle, said pinion being in mesh with said gear teeth, the arrangement being such that rotation of said auxiliary knob is effective to rotate said main knob at a lower angular velocity than that of the auxiliary knob.

3. In a control device for variable electrical apparatus a main knob, an auxiliary knob, and mechanism for drivingly interconnecting said knobs, said auxiliary knob being supported by said inain knob and having its axis of rotation at an angle to the axis of rotation of said main knob, said auxiliary knob being of substantially spherical form.

-l. In a control device for variable electrical apparatus a main knob, an auxiliary knob, and mechanism for drivingly interconnecting said knobs, said auxiliary knob being supported by said main knob and partly disposed within a recess in said main knob, said auxiliary knob being of substantially spherical form.

In testimony whereof I affix my signature.

LOUIS G. PACENT. 

